Modeling of Diesel Engine Energy Efficiency Parameters and Evaluation of Different Combustion Models

Abstract

This publication contains results of indicated diesel engine cycle parameters modelled using mathematical modeling AVL FIRE software. Purpose of research was to evaluate different combustion model adequacy to model indicated diesel engine cycle parameters. In order to achieve this purpose mathematical modeling was conducted using Eddy Breakup, Extended Coherent Flame-3Z, Characteristic Timescale models. Most accurate results were obtained using the Extended Coherent Flame-3Z model. At high engine load mode (HLM) this model had an error for the indicated mean effective pressure of 8%, for the indicated efficiency 10%, for the maximum cylinder pressure 8% and the difference in ignition delay was 2 CAD, however it did not perform well at low engine load mode (LLM) and had an error of 21% for indicated mean effective pressure, 19% for the indicated efficiency, 2% in the maximum cylinder pressure and the difference in ignition delay was 1 CAD. For the Characteristic Timescale and Eddy Breakup models the errors for indicated mean effective pressure were 13% and 14% in HLM and 16% and 13% in LLM respectively. One possible explanation for large errors in mathematical models is the difference in ignition delay between the experiment and mathematical models. The Characteristic Timescale and Eddy Breakup models had a difference in ignition delay of 4.5 CAD and 3.5 CAD respectively at HLM and 3.5 CAD at LLM.